An engineer appointed by the Mamata Banerjee government to inspect the Tallah bridge has said the structure is in a “rotten” condition and should be demolished, officials said.

The engineer has also said in his report that even light vehicles should not be allowed on the north Calcutta bridge for more than two months, by when all necessary traffic diversions must be worked out.

V.K. Raina, who was once a consultant to the United Nations and World Bank, had inspected the bridge on October 3 and handed over his report to chief secretary Rajiva Sinha on Wednesday.

Sources aware of the content of the report told Metro that Raina had described the condition of the bridge as “rotten” and expressed the fear that the structure might collapse any moment.

The report, said an official who has gone through it, has allowed a two-month period for the movement of light vehicles on the bridge only to let the authorities take the necessary measures for traffic diversion.

But officials in the state public works department (PWD), the custodian of the 57-year-old bridge, said they would recommend to the government that the structure be closed at the earliest. “We do not want to wait for two months,” an official said.

Commissioned in 1962, the Tallah bridge has strands of steel ducts supporting its underbelly. Engineers who inspected the bridge said many of the strands had snapped, which means they no longer have the ability to bear the load. “In such a situation, the bridge can collapse even if there is no extra load on it,” said one engineer.

Raina’s report does not contradict the one filed by the engineering consultancy RITES, which had inspected the bridge before him. The highway division of RITES, a subsidiary of the railways, had informed the Bengal government that the bridge was not fit even for pedestrians.

They had also told the government verbally that the bridge was beyond repair and would have to be demolished.

Sources said the PWD wanted to seek a second opinion after RITES had submitted its report. The department then approached Raina, who is considered an expert on bridges and has authored several books that are taught in engineering classes.

“The report prepared by V.K. Raina clearly says the bridge must be demolished. He has given the two-month period so that necessary traffic diversions can be worked out and there is no trouble during the festive season,” said an official who was present at the meeting on Wednesday where the report was tabled.

“Raina said at the meeting that the two-month period (for the movement of light vehicles) is based on the assumption that some cables can still bear load,” said the official.

The report states that only 7.5 metres of the 13-metre-wide bridge should be kept open for vehicular movement. The two footpaths must be closed and pedestrians should walk down the portion of the carriageway where vehicles are not allowed.

Only light vehicles — those with weight not more than 3 tonnes — are being allowed on the bridge. Buses and heavy goods vehicles have been barred from using it.

The diversions have resulted in huge snarls in surrounding areas such as Paikpara and Belgachhia.

Officials said chief minister Mamata Banerjee might attend a meeting at Nabanna on Saturday where the report would be discussed and the course of action decided.